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Java后台直接生成二维码介绍
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Java后台直接生成二维码
1、其实jquery也可以直接生成二维码的，但我测试的时候，二维码生成后太模糊，难以识别。所以在这里介绍在后来生成二维码的方式。
2、不善于文字描述，直接上代码了。
1 import java.awt.Graphics2D;
2 import java.awt.geom.AffineTransform;
3 import java.awt.image.BufferedImage;
4 import java.io.File;
5 import java.io.IOException;
6 import java.io.OutputStream;
7 import java.util.HashMap;
8 import java.util.Hashtable;
9 import java.util.Map;
10
11 import javax.imageio.ImageIO;
12 import javax.servlet.http.HttpServletResponse;
13
14 import org.slf4j.Logger;
15 import org.slf4j.LoggerFactory;
16
17 import com.google.zxing.BarcodeFormat;
18 import com.google.zxing.Binarizer;
19 import com.google.zxing.BinaryBitmap;
20 import com.google.zxing.DecodeHintType;
21 import com.google.zxing.EncodeHintType;
22 import com.google.zxing.LuminanceSource;
23 import com.google.zxing.MultiFormatReader;
24 import com.google.zxing.MultiFormatWriter;
25 import com.google.zxing.Result;
26 import com.google.zxing.common.BitMatrix;
27 import com.google.zxing.common.HybridBinarizer;
28 import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
29
30 /**
31 * <p>Title:QRCodeUtil </p>
32 * <p>Description: 二维码生成工具类</p>
33 * @author Administrator
34 * @version
35 * @since
36 */
37 public final class QRCodeUtil extends LuminanceSource {
38
39 private static final Logger logger = LoggerFactory.getLogger(QRCodeUtil.class);
40
41 // 二维码颜色
42 private static final int BLACK = 0xFF000000;
43 // 二维码颜色
44 private static final int WHITE = 0xFFFFFFFF;
45
46 private final BufferedImage image;
47 private final int left;
48 private final int top;
49
50 public QRCodeUtil(BufferedImage image) {
51 this(image, 0, 0, image.getWidth(), image.getHeight());
52 }
53
54 public QRCodeUtil(BufferedImage image, int left, int top, int width, int height) {
55 super(width, height);
56 int sourceWidth = image.getWidth();
57 int sourceHeight = image.getHeight();
58 if (left + width > sourceWidth || top + height > sourceHeight) {
59 throw new IllegalArgumentException("Crop rectangle does not fit within image data.");
60 }
61 for (int y = top; y < top + height; y++) {
62 for (int x = left; x < left + width; x++) {
63 if ((image.getRGB(x, y) & 0xFF000000) == 0) {
64 image.setRGB(x, y, 0xFFFFFFFF); // = white
65 }
66 }
67 }
68 this.image = new BufferedImage(sourceWidth, sourceHeight, BufferedImage.TYPE_BYTE_GRAY);
69 this.image.getGraphics().drawImage(image, 0, 0, null);
70 this.left = left;
71 this.top = top;
72 }
73
74 @Override
75 public byte[] getRow(int y, byte[] row) {
76 if (y < 0 || y >= getHeight()) {
77 throw new IllegalArgumentException("Requested row is outside the image: " + y);
78 }
79 int width = getWidth();
80 if (row == null || row.length < width) {
81 row = new byte[width];
82 }
83 image.getRaster().getDataElements(left, top + y, width, 1, row);
84 return row;
85 }
86
87 @Override
88 public byte[] getMatrix() {
89 int width = getWidth();
90 int height = getHeight();
91 int area = width * height;
92 byte[] matrix = new byte[area];
93 image.getRaster().getDataElements(left, top, width, height, matrix);
94 return matrix;
95 }
96
97 @Override
98 public boolean isCropSupported() {
99 return true;
100 }
101
102 @Override
103 public LuminanceSource crop(int left, int top, int width, int height) {
104 return new QRCodeUtil(image, this.left + left, this.top + top, width, height);
105 }
106
107 @Override
108 public boolean isRotateSupported() {
109 return true;
110 }
111
112 @Override
113 public LuminanceSource rotateCounterClockwise() {
114 int sourceWidth = image.getWidth();
115 int sourceHeight = image.getHeight();
116 AffineTransform transform = new AffineTransform(0.0, -1.0, 1.0, 0.0, 0.0, sourceWidth);
117 BufferedImage rotatedImage = new BufferedImage(sourceHeight, sourceWidth, BufferedImage.TYPE_BYTE_GRAY);
118 Graphics2D g = rotatedImage.createGraphics();
119 g.drawImage(image, transform, null);
120 g.dispose();
121 int width = getWidth();
122 return new QRCodeUtil(rotatedImage, top, sourceWidth - (left + width), getHeight(), width);
123 }
124
125 /**
126 * @param matrix
127 * @return
128 */
129 private static BufferedImage toBufferedImage(BitMatrix matrix) {
130 int width = matrix.getWidth();
131 int height = matrix.getHeight();
132 BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
133 for (int x = 0; x < width; x++) {
134 for (int y = 0; y < height; y++) {
135 image.setRGB(x, y, matrix.get(x, y) ? BLACK : WHITE);
136 }
137 }
138 return image;
139 }
140
141 /**
142 * 生成二维码图片
143 *
144 * @param matrix
145 * @param format
146 * @param file
147 * @throws IOException
148 */
149 public static void writeToFile(BitMatrix matrix, String format, File file) throws IOException {
150 BufferedImage image = toBufferedImage(matrix);
151 if (!ImageIO.write(image, format, file)) {
152 throw new IOException("Could not write an image of format " + format + " to " + file);
153 }
154 }
155
156 /**
157 * 生成二维码图片流
158 *
159 * @param matrix
160 * @param format
161 * @param stream
162 * @throws IOException
163 */
164 public static void writeToStream(BitMatrix matrix, String format, OutputStream stream) throws IOException {
165 BufferedImage image = toBufferedImage(matrix);
166 if (!ImageIO.write(image, format, stream)) {
167 throw new IOException("Could not write an image of format " + format);
168 }
169 }
170
171 /**
172 * 根据内容，生成指定宽高、指定格式的二维码图片
173 *
174 * @param text 内容
175 * @param width 宽
176 * @param height 高
177 * @param format 图片格式
178 * @return 生成的二维码图片路径
179 * @throws Exception
180 */
181 private static String generateQRCode(String text, int width, int height, String format, String pathName)
182 throws Exception {
183 Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
184 hints.put(EncodeHintType.CHARACTER_SET, "utf-8");// 指定编码格式
185 hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);// 指定纠错等级
186 hints.put(EncodeHintType.MARGIN, 1); // 白边大小，取值范围0~4
187 BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);
188 File outputFile = new File(pathName);
189 writeToFile(bitMatrix, format, outputFile);
190 return pathName;
191 }
192
193 /**
194 * 输出二维码图片流
195 *
196 * @param text 二维码内容
197 * @param width 二维码宽
198 * @param height 二维码高
199 * @param format 图片格式eg: png, jpg, gif
200 * @param response HttpServletResponse
201 * @throws Exception
202 */
203 public static void generateQRCode(String text, int width, int height, String format, HttpServletResponse response)
204 throws Exception {
205 Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
206 hints.put(EncodeHintType.CHARACTER_SET, "utf-8");// 指定编码格式
207 hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.L);// 指定纠错等级
208 hints.put(EncodeHintType.MARGIN, 1); // 白边大小，取值范围0~4
209 BitMatrix bitMatrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, width, height, hints);
210 writeToStream(bitMatrix, format, response.getOutputStream());
211 }
212
213 /**
214 * 解析指定路径下的二维码图片
215 *
216 * @param filePath 二维码图片路径
217 * @return
218 */
219 public static String parseQRCode(String filePath) {
220 String content = "";
221 try {
222 File file = new File(filePath);
223 BufferedImage image = ImageIO.read(file);
224 LuminanceSource source = new QRCodeUtil(image);
225 Binarizer binarizer = new HybridBinarizer(source);
226 BinaryBitmap binaryBitmap = new BinaryBitmap(binarizer);
227 Map<DecodeHintType, Object> hints = new HashMap<DecodeHintType, Object>();
228 hints.put(DecodeHintType.CHARACTER_SET, "UTF-8");
229 MultiFormatReader formatReader = new MultiFormatReader();
230 Result result = formatReader.decode(binaryBitmap, hints);
231
232 logger.info("result 为：" + result.toString());
233 logger.info("resultFormat 为：" + result.getBarcodeFormat());
234 logger.info("resultText 为：" + result.getText());
235 // 设置返回值
236 content = result.getText();
237 } catch (Exception e) {
238 logger.error(e.getMessage());
239 }
240 return content;
241 }
242
243 public static void main(String[] args) {
244 String text = "hello world!"; // 随机生成验证码
245 System.out.println("随机码： " + text);
246 int width = 100; // 二维码图片的宽
247 int height = 100; // 二维码图片的高
248 String format = "png"; // 二维码图片的格式
249
250 try {
251 // 生成二维码图片，并返回图片路径
252 String pathName = generateQRCode(text, width, height, format, "D:/new.png");
253 System.out.println("生成二维码的图片路径： " + pathName);
254
255 String content = parseQRCode(pathName);
256 System.out.println("解析出二维码的图片的内容为： " + content);
257 } catch (Exception e) {
258 e.printStackTrace();
259 }
260 }
261
262 }
3、需要添加的依赖
1 <dependency> 2 <groupId>com.google.zxing</groupId> 3 <artifactId>core</artifactId> 4 <version>3.3.0</version> 5 </dependency> 6
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